Interesting thread. I would say it does show his preference for kokyu myself.

Not so much - here's part of an interview with Yasuo Kobayashi (the original is in Japanese only):

Quote:

Q: Is that so - did that have the freestyle (jiyu-waza) demonstrations so common in Aikido at that time?
A: No, that began after the examination system was established. When the membership began to increase a system of kyu and dan examinations was instituted, and the uchi-deshi would take ukemi. However there were never more than around 5 uchi-deshi, so they could not partner up with the expanding number of students, so the students were made to partner with each other for ukemi. At that time freestyle was added as an item on the examination. We held demonstrations from the time that I started, but since basic techniques alone were thought to be boring it was decided to show kokyu-nage as well. Until that time kokyu-nage was not done often in the dojo.

Q: Why was that?
A: O-Sensei did not like kokyu-nage very much. "What good is simply throwing around people like that?" was his thinking. However it was good for training, so it was added to the normal practice. Aiki-nage was much the same - behind the scenes of how freestyle became introduced these kinds of things happened. While we're discussing this, as far as I know koshi-nage was not practiced much in the beginning. After Nishio and Kuroiwa researched it independently other instructors began to steal their techniques.